Discoporella gemmulifera Winston & Vieira, 2013

Almeida, Ana C. S., Souza, Facelucia B. C. & Vieira, Leandro M., 2021, Free-living bryozoans (Cheilostomatida, Cupuladriidae) from northeastern and northern Brazil, Zootaxa 4933 (1), pp. 39-62 : 49-51

Discoporella gemmulifera Winston & Vieira, 2013

( Figs 6 , 7 ; Table 2 )

Discoporella gemmulifera Winston & Vieira, 2013: p. 112 , fig. 9.

Discoporella umbellata: Marcus & Marcus, 1962: p. 290 , pl. 1, fig. 4, pl. 2, figs 5–7, pl. 3, figs 8–11, pl. 4, figs 13–19, pl. 5, figs 20–22; Almeida et al., 2015a: p. 3; Souza & Almeida, 2017: p. 265.

? Discoporella umbellata: Tommasi, 1967: p. 51 ; Tommasi et al., 1972: p. 139.

Non Lunulites umbellata Defrance, 1823: p. 361 , pl. 47, figs I, la, 1b.

? Discoporella umbellata subsp. depressa: Buge, 1975: p. 444 ; Cook, 1965a: p. 180, pl. 3, figs 2, 4.

Non Lunulites depressa Conrad, 1841: p. 348 .

Material examined. Holotype: MZUSP 718 , BIOTA /FAPESP/ Bentos Marinho Project col., BIOTA Stn 208, 23º43.442’ S, 45º18.914’ W, Ilhabela, S „o Paulo, 27 November 2002, 11 m, coarse sand . Additional specimens: UFBA 1494.2 , BA ( Abrolhos Archipelago ), 1 colony ; UFBA 182.4 , BA ( Ilhéus-Porto Seguro ), 4 colonies ; UFBA 2577.1 , BA ( Cairu ), 12 colonies ; UFBA 2239.4 , UFBA 2245.1 , UFBA 2613.1 , BA ( Maraú ), 3 colonies ; UFBA 168.3 , UFPE 544 , BA ( Off Baía de Todos os Santos), 14 colonies ; UFBA 248.1 , UFBA 750.1 , BA ( Baía de Todos os Santos), 11 colonies ; UFBA 164.3 , UFBA 194.2 , BA ( Salvador), 34 colonies; UFBA 576.1 , UFBA 576.2 , UFBA 576.3 , UFBA 2240.5 , UFBA 2244.2 , UFBA 2292.1 , UFBA 3273.1 , UFBA 3304.1 , UFPE 543 , BA ( Camaçari ), 9 colonies ; MOUFPE 42.4 - Akaroa 139, SE (Aracaju), 1 colony ; MOUFPE 40.4 - Akaroa 154, SE (Itaporanga d’Ajuda), 1 colony ; UFPE 532 , RN ( Guamaré ), 2 colonies ; MOUFPE 07.4 -MA14, MOUFPE 10.2 -MA13, MA (Cedral), 6 colonies; MOUFPE 23.2 -MA24, MOUFPE 35.4 -MA41, PA (Bragança), 2 colonies; MOUFPE 17.4 -MA34, PA (S„o Jo„o de Pirabas), 2 colonies; MOUFPE 36.2 -MA38, PA (Algodoal), 1 colony; MOUFPE 25.2 -MA39, PA (Salinópolis), 1 colony; MOUFPE 28.2 - MA49, PA ( Ilha do Mosqueiro), 1 colony ; MOUFPE 02.4 -MA56, MOUFPE 03.4 -MA62, MOUFPE 05.4 -MA60, MOUFPE 22.4 -MA59, MOUFPE 24.4 -MA68, AP (Macapá), 6 colonies; MOUFPE 27.2 - MA65, AP ( Araguari River Mouth), 1 colony .

Description. Colonies flat, discoidal ( Fig. 6A, B ), 1.5–6.1 mm in diameter (mean 2.5 mm; n = 30; standard deviation 0.4 mm). Central area of colony composed of oval to lozenge-shaped autozooids occluded by secondary calcification, with minute central and lateral frontal openings ( Figs 6A, B ; 7A ). Other autozooids rhomboidal to subhexagonal, separated by elevated lateral walls, with a D-shaped opesia ( Figs 6D ; 7B, C ) with smooth distal shelf. Cryptocystal shield granular, occupying two-thirds of opesia length, with 6–9 irregularly circular to subtriangular opesiules with denticulate margins. Vicarious heterozooids rhomboidal to subhexagonal, with distal shelf raised and granular ( Fig. 6C ); opesia subrectangular, with crenulated margin, occupying more than half of zooidal length, with smooth distal shelf; cryptocyst granular, wider laterally and proximally; gymnocyst as a narrow, raised marginal rim ( Figs 6B, D ; 7A ). Vibracular chamber subtriangular, located distally to each autozooid and avicularium; opesia auriform; paired and hooked mediolateral flaps; cryptocyst granular, short and wider proximally; chamber showing band of gymnocyst laterally and proximally ( Figs 6D , 7B ). Colony with no kenozooids or autozooids occluded by secondary calcification, with distinctly projecting vibracular marginal chambers ( Figs 6B , 7C ). Basal surface with radial grooves and high granular density ( Fig. 7D ).

Remarks. Many previous records of Discoporella from the Western Atlantic and Eastern Pacific were attributed to D. umbellata ( Cook 1965a; Herrera-Cubilla et al. 2008), including some specimens from Brazil (e.g. Marcus & Marcus 1962; Tommasi 1967; Tommasi et al. 1972). Cook (1965a) noted that D. umbellata sensu stricto, however, only occurs in the Eastern Atlantic ( Cook 1965a; see also Herrera-Cubilla et al. 2008), and other records of this species must represent other species. Thus, Cook (1965a) (and later Buge 1975) assigned specimens of nominal D. umbellata studied by Marcus & Marcus (1962), and additional specimens from Rio de Janeiro, S„o Paulo and Bahia (Abrolhos), to Discoporella umbellata subsp. depressa Conrad, 1841 . Cook (1965a) described and figured D. depressa from the type locality (Miocene, North Carolina, United States), showing that it has very large colonies (up to 18 mm in diameter), long autozooids (up to 0.700 mm), and vibracular chambers with the cryptocyst smooth (not granulated) proximally. Our Brazilian specimens have much smaller colonies (up to 6.1 mm in diameter), shorter autozooids (up to 0.504 mm long), and vibracular chambers with a narrow cryptocyst that is granulated proximally. Specimens that Marcus & Marcus (1962) attributed to D. umbellata are currently recognized as belonging to D. gemmulifera ( Winston & Vieira 2013) . The main differences between D. gemmulifera and D. umbellata include the number of opesiules (6–9 in D. gemmulifera ; 8–14 in D. umbellata ) and the opesia (without denticles in D. gemmulifera and with proximal denticles in D. umbellata ) ( Cook 1965a; Herrera-Cubilla et al. 2008; Winston & Vieira 2013). We suspect that most of the specimens from Brazil that have flat, discoidal colonies, and were previously misassigned to either D. umbellata or D. depressa (i.e. Tommasi 1967; Tommasi et al. 1972; Buge 1975), may also belong to D. gemmulifera . A review of the records of Tommasi (1967) and Tommasi et al. (1972) will be necessary to resolve this issue; the relevant specimens were located in 2010 by L.M. Vieira in the Bryozoa collection of the MZUSP, but currently we cannot access these specimens for comparison.

Among species of Discoporella , D. gemmulifera most resembles D. bocasdeltoroensis Herrera-Cubilla, Dick, Sanner & Jackson, 2008 , D. marcusorum Herrera-Cubilla, Dick, Sanner & Jackson, 2008 and D. peltifera Herrera-Cubilla, Dick, Sanner & Jackson, 2008 in having discoidal colonies with semi-determinate growth. These species have a maximum colony size larger than in D. gemmulifera (up to more than 8 mm in diameter in D. bocasdeltoroensis , D. marcusorum and D. peltifera ; up to 6.1 mm in diameter in D. gemmulifera ). Other differences between D. gemmulifera and D. bocasdeltoroensis are the number of opesiules (6–9 in D. gemmulifera ; 3–10 in D. bocasdeltoroensis ), and the shape of the opesia (D-shaped in D. gemmulifera ; oval in D. bocasdeltoroensis ). Discoporella gemmulifera differs from D. marcusorum also in having a smaller opesia (mean 0.106 mm long by 0.112 mm wide in D. gemmulifera ; mean 0.120 mm long by 0.140 mm wide in D. marcusorum ), and smaller autozooidal vibracula (0.074 –0.153 mm long by 0.079 –0.180 mm wide in D. gemmulifera ; 0.160 –0.230 mm long by 0.130 –0.190 mm wide in D. marcusorum ). Differences between D. gemmulifera and D. peltifera include the morphology of the opesiules (with weakly developed spinous processes in D. gemmulifera ; occluded in D. peltifera ) and the presence of kenozooids (not seen in D. gemmulifera ; marginal in D. peltifera ) ( Herrera-Cubilla et al. 2008).

Distribution. Western Atlantic: Brazil (S„o Paulo, Bahia, Sergipe, Rio Grande do Norte, Maranh„o, Pará and Amapá) ( Almeida et al. 2015a; Souza & Almeida 2017; present study).

Figures

FIGURE 6. Discoporella gemmulifera Winston & Vieira, 2013. A, B. Frontal view of colonies in different astogenetic stages (vicarious heterozooid indicated by arrows). A. UFBA 576.3, 2.4 mm in diameter. B. UFBA 576.1, 4.2 mm in diameter. C. UFBA 576.1, Detail of vicarious heterozooid and its vibracular chamber. D. UFBA 576.1, Detail of vibracular chambers. Scale bars: A, B. 1 mm; C. 200 µm; D. 100 µm.

FIGURE 7. Discoporella gemmulifera Winston & Vieira, 2013. A–D. UFBA 576.1, Bahia, Brazil. A. Autozooids in the central area of the colony and a vicarious heterozooid (arrow). B. Group of autozooids and its vibracular chambers. C. Marginal autozooids with distinct projecting vibracular marginal chambers. D. Colony basal view. Scale bars: A, D. 500 µm; B, C. 200 µm.